Researchers have demonstrated the highest efficiency to date of a lower cost method of converting sunlight into electricity patterned around photosynthesis.

Alternatives to silicon solar cells
There are many ways to make solar cells that capture light and produce electricity. One alternative to expensive traditional, but expensive, silicon based solar cells is known as dye-sensitized solar cells (DSCs) that use lower cost light collecting compounds to improve performance. These systems can be used in flexible thin film solar cells.

Low cost solar cells
Swiss Resseachers developed the Gratzel cell, or dye sensitized, in the early 1990s in an effort to mimic the basic photoelectochemical process of photosynthesis. Dye Sensitized Solar Cells use cheap titanium dioxide (TiO2 ) particles coated with a dye to absorb a wide range of wavelengths given off by sunlight. University of Washington researchers have described the structure as ‘popcorn’ solar cells (Image).

The core problem of these solar cells is that the material breaks down rapidly after being exposed to sunlight. But last month Chinese and Swiss researchers reported the highest efficiency to date (9.6-10.0%) using thin film of titanium dioxide (TiO2) solar cell that retained over 90% of the initial performance after 1000 hours of full sunlight soaking at 60 °C. In September Michael Gratzel’s group reported 11.3% efficiency.

If researchers can continue to overcome the basic performance barriers, dye sensitized solar cells could lead to an era of lower cost solar energy. There are a few notable commercial applications. Earlier we posted a story of solar startup Konarka’s plan to open a 1 gigawatt manufacturing plant in 2009.